1. Field of the Invention
This invention relates to the production of titanium tetrachloride utilising as a raw material an iron-containing titaniferous ore or ore concentrate.
2. Brief Description of the Prior Art
Titanium tetrachloride may be produced from such ores by chlorinating the ore or ore concentrate selectively in a fluid bed so that the iron values present in the ore are converted to iron chlorides which are removed from residual titanium values in the ore beneficiate. The residual titanium values may then be chlorinated, in a separate operation, to titanium tetrachloride. This method of producing titanium tetrachloride involves the loss of a certain proportion of the titanium values in the ore by chlorination and removal as vapour with the iron values since in practice the degree of selectivity of chlorination of the iron values will fall somewhat short of theoretical. A further disadvantage of this method is that a high heat load is placed on the fluid bed as a result of removing hot beneficiate from the bed. To replace the heat removed a feed preheater is required and this is expensive both in first cost and in fuel. To avoid these disadvantages attempts have been made to produce titanium tetrachloride by chlorinating both the iron and titanium values in the ore, removing the resulting iron and titanium chlorides as a vaporous mixture and then separating the iron chloride from the titanium chloride by condensation of the iron chloride to a solid. The recovery of chlorine from the condensed iron chloride requires volatilization thereof with an accompanying heat requirement which makes the recovered chlorine relatively expensive.
It would be desirable to recover the chlorine from the iron chlorides in the vapor phase, thus eliminating this heat requirement by, for example, oxidizing the iron chlorides in the vapour phase to produce iron oxide and molecular chlorine. Such an oxidation is readily accomplished in the substantial absence of titanium tetrachloride as is disclosed in U.S. Pat. No. 3,865,920. In the presence of substantial quantities of titanium tetrachloride oxidation under the conditions disclosed in that patent would lead to simultaneous oxidation of an appreciable proportion of the titanium tetrachloride and the resulting titanium dioxide would be lost as an impurity of the iron oxide produced.